Method of making tubular sheet material



Feb. 13, 1940. TEMPMNv 2,190,494

METHOD OF MAKING TUBULAR SHEET MATERIAL Fil ed Oct. 4, 1937 INVENTOR.R/cr/A RD L. TEMPL/N.

Patented Feb. 13, 1940 PATENT OFFICE METHOD OF MAKING TUBULAR SHEETMATERIAL Richard L. Templin, New kensington, Pa., assignor to AluminumCompany of America, Pittsburgh, Pa.,' a corporation of PennsylvaniaApplication October 4, 1937, Serial No. 167,124

5 Claims.

This invention relates in general to the production of hollow ortubularjsheet or plate material. In particular, and in its preferredform, the invention relatesto the production of a rela 5 tively thinsheet metal product provided with internal tubular apertures.

There is an ever increasing demand for tubu lar structural material insheet form which is adaptable to the construction of fluid circulatingsystems, such as heat exchange systems, heat radiating systems,refrigeration systems, hot plates and the like. For such purposes, ithas been known to employ built-up units from individual tubes providedwith fins, or relatively heavy cast units, wherein wrought tubularmembers are incorporated in a cast metal body structure, most, if notall of which, have incorporated in their construction complicated,soldered, and

' welded joints.

:0 It is an object of the present invention to overcome the necessity ofresorting to complex and cumbersome constructions, as well as units"comprised of two or more dissimilar metals, in the manufacture of unitsand devices requiring is internally apertured material, by providing ametal product in stock form from a single alloy or composition, and inquantities from which the numerous devices in question may beconstructed. It will be manifest that the sheet ma- 0 terial of thisinvention will'be representative of a monometallic sheet product whichis of greatly reduced weight per unit of length, and will thereforeadapt itself to structural uses other than those specifically mentionedherein.

5 Other objects, including maximum economy of material and labor,represented by this invention will be apparent to those skilled in thisart on consideration of the following description taken in conjunctionwith the drawing, in which:

V Figure 1 illustrates a top planview of a slab or blank of initial orstarting material;

Figure 2 illustrates "an end view of the slab represented in'Figure 1;

Figure 3 illustrates an end view of the slab 5 represented in Figure 1at an intermediate stage in the production of,the final-product oftheinvention;

Figure 4 illustrates an end view of the preferred final product of theinvention; and

| Figure 5 illustrates-a modified form of the final product of theinvention.

when described in its most general terms. the

invention comprises subjecting an initial blank or slab of material,having one or. more internal tubular-apertures, to a working or seriesof progressive working operations to partially or completely,dimensionally transform the initial slab. This starting or initialmaterial may be produced in any suitable manner, such as by extrusion,permanent mold casting, die and/or 5 pressure casting, or sand casting.The initial slab is preferably of thicker -gauge, or wider dimensionthan that finally desired, and in its preferred form is provided with anexcess of metal or protuberance adjacent-an internal apertime onopposite exterior faces of lthe initial blank. In some instances,however, a single protuberance adjacent the internal aperture anddisposed on the exterior face of the blank or slab may be sufiicient forthe purpose of this invention. An initial blank of either of the formsafore-described is finally subjected to any suitable working operation,such as rolling,

' drawing through a die, or the like, to dimensionally transform, orcompletely obliterate, the excess metal and. transform the blank to onehaving the required final form. It will be understood that, in thepreferred embodiment of the invention, any further reduction of gauge,following obliteration of the excess metal, will elongate the slab tosheet proportions with an attendant further transformation in the shapeand size of the internal aperture or apertures,

it being possible, and in most instances desirable, to reduce the wallthickness of an aperture, as measured in the plane of the gauge of theworked sheet material, to a point which could not otherwise beaccomplished by any known means of manufacture. The original slab beingthicker than that usually required in the 5 final preferred product,allows for greater ease in producing the internal apertures in theinitial slab, and the subsequent working imparts the desirablecharacteristics attributable to a cold and/or hot worked product. Also,where the metal of the blank is only subjected to a partial dimensionalchange, the same advantages willbe obtained.

Referring specifically to the .illustrations represented in the drawingaccompanying the speci- 5 fication, Figure 1 represents a slab ofmaterial III in plan view, provided with longitudinal aper-. tures Hextending throughout the length of the slab. This'slab may be cast orproduced by extrusion, the-latter process of production being '50preferred when it is desired to produce the novel Product of thisinvention from non-ferrous metals, and particularly from aluminum andits alloys. The extrusion process lends itself readily to accuracy indimension and duplication of production with a minimum of labor andtools, anddisplaced with an attendant reduction in the apertures ll donot necessarily extend throughout the length of the product of theinitial blank I0, where methods of manufacturing the initial blank aredistinguished from a strictly extrusion operation.

Figure 2 illustrates an end view of the initial slab or bloom. From thisview, it will be noted that the internal apertures II are circular incross section, and that excess metal is provided in the formofprotuberances l2 adjacent each aperture and disposed on opposite sidesof the initial slab or blank along the plane of the gauge of the blank.This excess metal serves to reinforce the aperture during the productionof the initial slab, distribution of the metal adjacent the aperturesinsuring complete filling out of the slab or bloom, if extruded, andlikewise insuring suflicient support for cores, or the like, if acasting operation is resorted to in the production of the initialmaterial. Also, the excess metal l2 serves to equalize the stressesinherent in the initial slab Ill, regardless of its method ofproduction, and permits a much larger original aperture H. with itsattendant 'ease in production, than thatfinally required or desired.Although the apertures II have been illustrated as circular in crosssection, in the original slab or bloom, it is to be understood thatthese internal apertures may take any desired or suitable crosssectional configuration, with equally successful results in the furtherpractice of this invention.

Figure 3 illustrates an end view of slab l0 following a workingoperation, such as a progressive rolling or die drawing operation,vand

represents a form of the product of the inven-' tion at an intermediatestage in its production. It is to be noted thatthe protuberances l2 havebeen reduced in thickness, as measured in the plane of the gauge of thematerial, and that the apertures II have become slightly ellipticalor'lenticular in cross section with only an appreciable change in majoraxial dimension. The cross sectional transformation of the apertures IIwill be manifest when it is considered that the directional rollingelongates the initial slab it without any appreciable change in width ofthe initial slab or blank.

In Figure 4, the protuberances or ribs 12 have been completelyobliterated and progressively worked or rolled into the surface of theslab I0,

and the apertures II have reached their final cross sectional form.Further rolling will serve to reduce the gauge of the slab I0 and reducethe wall thickness of the apertures H, as measured alongthe gauge lineof the slab. This condition is often desirable, particularly when theproduct of the invention is to be used in the subsequent construction ofheat exchange equipment, since ready transfer of heat is a functionofthe rate of transfer of heat through the wall thickness of the tubularproduct. t

Figure" 5 illustrates a modified form of end product which can beproduced from the original 'or initial blank III, in accordance with thepractice of this invention. In this embodiment of the invention, theslab or blank I0 is subjected to a working or series of workingoperations, such as by die drawing or edge working, whereby the metal ofthe protuberances I2 is laterally overall width of the initial blank. Asa result of this type of working, the protuberances 12 are decreasedin'width and increased in height, while the apertures II are transformedto elliptical or lenticular' cross section with their major axes in thevertical plane.. Manifestly, the working operations could be performedin a manner to produce a final product in which'the major axes of theapertures II and the disposi-- tion of the protuberances I! would beangularly disposed'if desired.

From the above general and specific description and explanation, it willbe appreciated that the process and product of this invention haveeliminated cumbersome .forming, machining, welding, and other operationsof like character now known to this art. It will alsobe understood thatthe invention makes it possible to produce a stock product in wroughtsheet form which may be cut into lengths and employed in any number ofconstructions. The tubular sheet product of this invention readilyadapts itself to forming operations, and wherever light-. ness inweight, for a given thickness, but an otherwise plane surface isrequired, the product herein described as the preferred form of the-invention (Figure 4) finds ready adaptability.

. fore, the exact form shown is to be taken as illustrative only and notin a limiting sense, and it is desired that only such limitations shallbe placed thereon as are imposed by the prior art, or are specificallyset forth in the appended claims.

What I claim is:

1 The method of producing an apertured metal product comprising thesteps, extruding a blank having an internal aperture and an excess ofmetal of uniform cross section coextensive with, adjacent and exteriorto the aperture as measured in the plane of the gauge of the blank, andsubsequently submitting the excess metal to a progressive rollingoperation to uniformly displace the same and simultaneously change thecross sectional configuration of the internal aperture, said blank beinginteriorly unsupported during the rolling operation.

2. The method of producing an apertured metal product comprising thesteps, extmding a blank having an internal aperture and an excess ofmetal of uniform cross section coextensive with, adjacent and exteriorto the aper ture as measured in the plane of the gauge of the blank, andsubsequently submitting the blank to a progressive rolling operation toobliterate the excess metal and simultaneously change the crosssectional configuration of the internal aperture, said blank beinginteriorly free from support within said aperture during the rollingoperation.

3. The method of producing an apertured product comprising; the steps,extruding a blank having an internal aperture and an excess of materialof the blank of uniform cross section coextensive with, adjacent andexterior to the aperture as measured in the plane of the gauge -of theblank, and subsequently submitting theblank to a progressive rollingoperation to uniformly displace the excess material and simultaneouslychange the cross sectional configuration of the internal aperture, saidblank being interiorly unsupported during the rolling operation.

4. The method of producing an apertured wrought sheet metal productcomprising the steps, extruding a blank having an aperture extendinginto the interior thereof and an excess of metal of uniform crosssection coextensive with, adjacent and exteriorto the aperture in theplane of the gauge of the blank, and thereafter subjecting the blank toa progressive rollsimultaneously changed, the blank being interiorlyfree from support Within said aperture during said rolling operation.

5. The method of producing an apertured metal product comprising thesteps, extruding a blank having an internal aperture and an excess ofmetal coextensivev with, adjacent and exterior to the aperture asmeasured in the plane of the gauge of the blank, and subsequentlysubmitting the blank to a progressive rolling operation to obliteratethe excess metal and simultaneously change the cross sectionalconfiguration oi the internal, aperture, said blank being interiorlyfree from support within said aperture during the rolling operation.

RICHARD L. TEMPLIN.

